iio: potentiometer: max5487: Don't return an error in .remove()

The only effect of returning an error in an spi .remove() callback is
that the spi core issues a generic warning message. Instead emit a more
specific error message and return 0 to not report the same issue twice.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: Alexandru Ardelean <ardeleanalex@gmail.com>
Link: https://lore.kernel.org/r/20211013203223.2694577-15-u.kleine-koenig@pengutronix.deSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/potentiometer/max5487.c

@@ -115,11 +115,16 @@ static int max5487_spi_probe(struct spi_device *spi)
 static int max5487_spi_remove(struct spi_device *spi)
 {
 	struct iio_dev *indio_dev = spi_get_drvdata(spi);
+	int ret;
 
 	iio_device_unregister(indio_dev);
 
 	/* save both wiper regs to NV regs */
-	return max5487_write_cmd(spi, MAX5487_COPY_AB_TO_NV);
+	ret = max5487_write_cmd(spi, MAX5487_COPY_AB_TO_NV);
+	if (ret)
+		dev_warn(&spi->dev, "Failed to save wiper regs to NV regs\n");
+
+	return 0;
 }
 
 static const struct spi_device_id max5487_id[] = {